1. Field of the Invention
The present invention relates to a semiconductor device producing apparatus and a producing method of a semiconductor device, and more particularly, to a semiconductor device producing apparatus and a producing method of a semiconductor device which are effectively utilized for subjecting a semiconductor wafer or semiconductor wafers to thermal processing such as annealing processing, oxide film-forming processing, diffusion processing and film-forming processing.
2. Description of the Related Art
Generally, in a producing method of a semiconductor device, a batch-type vertical hot wall thermal processing apparatus (thermal processing apparatus, hereinafter) is widely used for subjecting a semiconductor wafer (wafer, hereinafter) into which an integrated circuit including a semiconductor element is incorporated to thermal processing such as annealing processing, oxide film-forming processing, diffusion processing and film-forming processing.
There exists a conventional thermal processing apparatus of this kind as described in Japanese Patent No. 2681055. In this thermal processing apparatus, a boat exchanging apparatus is disposed between a wafer transfer apparatus and a space directly below a process tube, a pair of (two) boats are placed on a rotating table of the boat exchanging apparatus, the pair of boats are rotated by 180 (around the rotating table so that an unprocessed boat and a processed boat are exchanged. That is, in this thermal processing apparatus, while one of the boats (first boat) holding a group of wafers is processed in a processing chamber of the process tube, new wafers are transferred to the other boat (second boat) by a wafer transfer apparatus.
Generally, film-forming processing time of the thermal processing apparatus is one to two hours although the time differs depending upon the kind of film to be processed by the thermal processing apparatus. On the other hand, time required for transferring 150 new wafers to the boat by the wafer transfer apparatus is about 12 minutes. In the above-described thermal processing apparatus, a group of new wafers are on standby outside of the processing chamber for a long time as long as one to two hours until the processing of the first boat is completed. If the group of new wafers transferred to the second boat is exposed to atmosphere outside the processing chamber, an unintended oxide film (natural oxide film, hereinafter) in terms of control is adversely formed on a surface of the wafer by moisture and oxygen existing in atmosphere. This natural oxide film exerts an adverse effect on variation of film-thickness processed by a wafer, or increases a contact resistance. Therefore, the natural oxide film exerts an effect on enhancement of packing density of a circuit, a quality (precision, lifetime and the like), performance (computation speed and the like) and reliability of a semiconductor integrated circuit apparatus (IC, hereinafter) produced by the wafer.